Power and communications cable for coiled tubing operations

ABSTRACT

A power and communications cable may include an electromagnetic waveguide, an inner metallic tubular surrounding the electromagnetic waveguide, an electrically conductive material surrounding the inner metallic tubular, an electrically insulating material surrounding the electrically conductive material, and an outer metallic tubular resistant to corrosion and abrasion surrounding the electrically insulating layer. The example system may include an electrical device locatable in the wellbore and coupleable to the cable and a control unit coupleable to the cable and operable to supply power to and communicate with the electrical device via the power and communications cable.

BACKGROUND

This section is intended to provide relevant background information tofacilitate a better understanding of the various aspects of thedescribed embodiments. Accordingly, it should be understood that thesestatements are to be read in this light and not as admissions of priorart.

Coiled tubing refers to relatively flexible, continuous tubing that canbe run into the wellbore from a large spool which may be mounted on atruck or other support structure. Coiled tubing may be used in a varietyof wellbore servicing operations including drilling operations,completion operations, stimulation operations, production operations,etc. Coiled tubing may also be used to inject fluids, which can beabrasive and/or corrosive, at high pressures to perforate the formation,fracture the formation, remove scale from production tubing or downholeequipment, or perform other suitable fluid injection operations.Electrical instruments (e.g., video cameras, pressure sensors,temperature sensors, etc.) can provide real-time access to downholeconditions to monitor coiled tubing operations. The electricalinstruments may rely on electrical power and communications to receivecommands and transmit measurements and other information to the surface.One method of providing power and communications to the electricalinstruments deployed via coiled tubing is employing a cable, whichcarries fiber optic and electrical cables, inside the coiled tubing.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention are described with reference to thefollowing figures. The same numbers are used throughout the figures toreference like features and components. The features depicted in thefigures are not necessarily shown to scale. Certain features of theembodiments may be shown exaggerated in scale or in somewhat schematicform, and some details of elements may not be shown in the interest ofclarity and conciseness.

FIG. 1 is a schematic diagram of a coiled tubing system deployed in awellbore intersecting a subterranean formation, according to one or moreembodiments;

FIGS. 2A-D are cross-sectional views of a power and communications cablepositioned along the coiled tubing, according to one or moreembodiments;

FIG. 3 is a cross-sectional view of the power and communications cable,according to one or more embodiments; and

FIG. 4 is a cross-section view of the power and communications cablewith an additional electrically conductive layer, according to one ormore embodiments.

DETAILED DESCRIPTION

Systems and methods of the disclosed embodiments may include a power andcommunications cable that can withstand the abrasive, corrosive fluidand high pressures (up to 15,000 psi/10⁸ Pascals) encountered inside thecoiled tubing. Embodiments of the cable may use waveguides to transmitcertain signals (e.g., sensor measurements from downhole tools to anuphole control unit, or vice versa) while surrounding layers of thecable are used to protect the waveguides. These surrounding layers mayalso be used to transmit power for operation of downhole tools, andtelemetry signals to receive and transmit commands to othercommunication targets. Thus, embodiments of the cable may provide thebenefits of withstanding pressure, resisting abrasion, resistingcorrosion, and conducting power and telemetry signals downhole.

FIG. 1 is a schematic diagram of a coiled tubing system 100 inaccordance with one or more embodiments. As shown, a wellbore 12 formspart of a completed production well 13 which includes a casing 14extending from the surface to the production formation 15 of the well.The production formation 15 may be several thousand feet into the earth,under intense pressure and heat with production fluids of hydrocarbonsin reserve to be extracted. The casing 14 includes a plurality ofperforations 16 formed in the wall thereof to allow the influx of theproduction fluids from the producing formation into the wellbore forremoval at the wellhead. A production packer 20 is positioned between astring of production tubing 17 and the casing 14 above the productionformation 15. Although FIG. 1 depicts the coiled tubing system 100employed in a production operation, it should be appreciated that thecoiled tubing system 100 may be used in a variety of oil and gasservicing operations, including drilling operations, interventionoperations, completion operations, and stimulation operations. Thecoiled tubing system 100 may also be used in offshore applications wherethe coiled tubing system 100 is employed on an offshore vessel (notshown).

The string of production tubing 17 extends from the wellhead productioncompletion equipment 18, for example, a “christmas tree,” to allow theproduction fluids flowing into the casing 14 from the formation to bereceived at the surface for collection of production fluids from thewell. The various valves 19 at the completion equipment 18 control theflow of production fluids brought to the surface through the tubing.

The coiled tubing system 100 comprises a truck 22 having a mechanicallyoperated coil 23. A continuous length of coiled tubing 24 capable ofwithstanding relative high pressures (e.g., up to 15,000 psi or above)is wound around the coil 23. The tubing 24 is slightly flexible so as tobe able to allow coiling of the tubing onto the coil 23. A hydrauliccrane 26 suspends a coiled tubing injector 25 over the completionequipment 18. The injector 25 includes a curved guideway 27 and ahydraulic injector that injects the coiled tubing 24 down into the welltubing 17 while the well remains under production pressure. The injector25 injects enough tubing 24 into the production tubing 17 that aninspection tool 30 attached to an end 28 of the tubing 24 protrudes fromthe production tubing 17 and into the region of the wellbore inside thecasing 14.

The inspection tool 30 includes an electrical device 29 that is used todetect temperature or pressure, or to take other readings of conditionsor conduct other downhole operations. A power and communications cable33 extends longitudinally inside or outside the coiled tubing 24 and isused in connecting the electrical device 29 with a control unit 44 asfurther described herein. The coiled tubing 24 conducts injection fluidsfrom the truck 22 to a location within the wellbore 12 that is selectedby the positioning of an injection nozzle 32. The fluid may be injectedinto the wellbore 12 under pressurized conditions to perform anoperation such as treating the formation 15. The injection fluid mayalso contain abrasive and corrosive chemicals and/or additives. Theadditives may corrode and abrade the components of the system 100 aswell as the formation 15, and thus the power and communications cable 33may experience high pressures as well as corrosive and abrasiveconditions.

The power and communications cable 33 is coupled to one or moreelectrical devices 29, such as a sensor 31, positioned in the wellbore12. The electrical device 29 may include additional or alternativesensors for monitoring downhole conditions, such as a video imagingsensor, a pressure sensor, a temperature sensor, etc. It should beappreciated that the sensor 31 is a non-limiting example of anelectrical device 29 positioned in the wellbore 12. The power andcommunications cable 33 may be coupled to various electronic orelectrical devices used for drilling operations, completion operations,stimulation operations, production operations, logging operations, etc.

The power and communications cable 33 has protective components thatensure the signals from the control unit 44 communicate to theelectrical device 29. For example, the power and communications cable 33may include a coaxial cable for high frequency data communications.Additionally or alternatively, electromagnetic waveguides (such as fiberoptic cables) may be used to improve the capacity of transmittable dataand also reduce the diameter and weight of the cable 33.

The coiled tubing system 100 also includes an operator control housing41 and a pair of pumps 42 connected to the upper end 43 of the coiledtubing 24 to pressurize the injection fluids into the coiled tubing 24from the surface. The pumps 42 are connected to a supply fluid (notshown). The control unit 44 may be located within the operator housing41 and controls the operation of the pumps 42 and the electrical device29 (e.g., the sensor device 31) positioned in the wellbore 12. The powerand communications cable 33 extends longitudinally along the coiledtubing 24 (e.g., inside or outside of the coiled tubing 24) and isconnected to the control unit 44, which includes an input device 45(e.g., a keypad, keyboard, touchpad, mouse, touchscreen, etc.) andoutput device 46 (e.g., a display, printer, touchscreen, etc.). Thecoiled tubing system 100 also includes the equipment required to sealoff the fluid in the tubing from the cable connections, convert theoptical signal to an electrical signal, and communicate that signal tothe control unit 44. The power and communications cable 33 is used tocarry both electrical power and communication signals downhole from thecontrol unit 44 to power the electrical device 29 positioned in thewellbore 12 as well as carry communication signals uphole from theelectrical device 29 to the control unit 44.

FIGS. 2A and 2B are cross-sectional views (not to scale) of the powerand communications cable 33 positioned inside or outside of the coiledtubing (schematically depicted at 24), in accordance with one or moreembodiments. As shown in FIG. 2A, the cable 33 may be positioned insideextending longitudinally along the coiled tubing 24. The cable 33 may bemechanically and electrically coupled to the coiled tubing in anysuitable manner such as by welding, brazing, soldering, mechanicallyfastening, or adhesive bonding the cable 33 to the coiled tubing 24. Thecable 33 may be integrated with and coupled to the coiled tubing 24while the coiled tubing 24 is being manufactured. The cable 33 may alsobe positioned inside the coiled tubing 24 by pulling the cable 33through the coiled tubing 24 with or without being coupled to theinterior of the coiled tubing 24. As shown in FIG. 2B, the cable 33 maybe positioned on the outside extending longitudinally along the coiledtubing 24 and coupled to the coiled tubing 24 while the coiled tubing 24is injected into the wellbore 12 with the coiled tubing injector 25.

FIGS. 2C and 2D are cross-sectional views (not to scale) of optionalexample embodiments in which the coiled tubing 24 has a predefinedchannel or cable guide indicated in both figures at 55, which may beformed during manufacturing of the coiled tubing 24, to at leastpartially position, guide, and/or secure the cable 33 to the coiledtubing 24. Although the cable guide examples are illustrated as arcuatechannels for receiving a generally circular cable 33, any other shapesor configurations are within the scope of this disclosure. As shown inFIG. 2C, the cable guide 55 may be an enclosed or partially enclosedchannel formed in the wall of the coiled tubing 24 to enclose the cable33. As shown in FIG. 2D, the cable guide 55 may only partially encirclethe cable 33, leaving a portion exposed either interior (or optionallyexterior) to the coiled tubing 24.

FIG. 3 shows a cross-section view of the power and communications cable33, in accordance with one or more embodiments. As shown, the cable 33includes one or more electromagnetic waveguides 50, such as fiber opticcables, extending longitudinally inside an inner metallic tubular 54,which may be made of steel, and held in position by a potting material52, including a silicone gel or epoxy. The inner metallic tubular 54 andthe electromagnetic waveguides 50 may be formed as an assembly referredto as fiber in metal tube (FIMT). The electromagnetic waveguides 50facilitate communications between downhole electrical equipment and thesurface. The electromagnetic waveguides 50 may be used to carrymeasurements of downhole conditions taken by the electrical equipmentpositioned in the wellbore 12 or carry command signals from the surfaceto the electrical equipment positioned in the wellbore 12. Theelectromagnetic waveguides 50 may include single mode or multimode fiberoptic cables.

While some sensors may communicate with the control unit 44 through theelectromagnetic waveguides 50, the cable 33 further comprises componentsthat comprise a plurality of concentric layers bonded, joined, and/orotherwise tightly bound. To supply power or provide anothercommunications channel to the electrical device 29, the cable 33 mayinclude an electrically conductive material 56 surrounding the innermetallic tubular 54. For example, the conductive material 56 may includea conductive tape (e.g., copper tape). The conductive tape may be woundaround the inner metallic tubular 54 without overlapping itself. Theelectrical conductive material 56 over metallic tubular 54 may present acurrent carrying cross section equivalent to size 10 of the AmericanWire Gauge (AWG).

The cable 33 may further include an electrically insulating layer 58surrounding the electrically conductive material 56 to electricallyseparate the inner metallic tubular 54 and the conductive material 56from further conductive paths within the cable 33. As a non-limitingexample, the electrically insulating layer 58 may include a fluorinatedethylene propylene (FEP), poly-tetrafluoroethylene (PTFE),ethylene-tetrafluoroethylene (ETFE), or other fluoropolymers.

The outermost concentric layer of the cable 33 may be an outer metallictubular 60. The outer metallic tubular 60 provides protection from thepressure and abrasion that may be present within and without the coiledtubing 24. As an additional benefit, the outer metallic tubular 60 mayprovide a conductive return path for the electric power signal orcommunication signal that propagates through the cable 33. Theelectrically insulating layer 58, the electrically conductive material56, and the inner metallic tubular 54 may fill the volume within theouter metallic tubular 60. To fit within the coiled tubing 24, the outermetallic tubular 60 may have an outer diameter (OD) of 3 to 6millimeters, for example 4 millimeters, but may also have a largerdiameter, e.g., up to 18 millimeters. The values of resistance describedherein in correspond to the cable 33 having an outer diameter of 4millimeters.

The outer metallic tubular 60 may include a corrosion and abrasionresistant alloy including a nickel alloy referred to as Nickel Alloy 825or a steel alloy referred to as Steel Alloy 316L. Corrosion and abrasionresistant means that the alloy may contact corrosive influences such assour gas (H₂S) without corroding. The nickel alloy of the outer metallictubular 60 may be a composition of metals comprising 38% to 46% ofnickel, at least 22% of iron, 19% to 23.5% of chromium, 2.5% to 3.5% ofmolybdenum, 1.5 to 3% of copper, at most 1% of manganese, and 0.6 to1.2% of titanium. The nickel alloy of the outer metallic tubular 60provides a suitable resistance per length of 185 Ω/km (56.4 Ω/k′) forpower and communications transmission. To resist corrosion and abrasionas well as withstand the demands of use in the coiled tubing 24, theouter metallic tubular may also comprise a steel alloy, which has aresistance in Ω/km 35% lower than the nickel alloy. The steel alloy mayinclude corrosion and abrasion resistant alloy referred to as SteelAlloy 316L. The steel alloy of the outer metallic tubular 60 may be acomposition of metals comprising 0.03% of carbon, 2.0% of manganese,0.75% of silicon, 0.045% of phosphorus, 0.03% of sulfur, 16.0 to 18.0%of chromium, 2.0 to 3.0% of molybdenum, 10.0 to 14.0% of nickel, and0.10% of nitrogen. Although not depicted in the figures, the outermetallic tubular 60 is electrically coupled at the end of the cable 33to the electrical device 29 in the wellbore 12 and at the surface toensure that the current flow splits between the two paths.

The cable 33 may be employed to transmit electrical power downhole viathe inner metallic tubular 54, the electrically conductive material 56,and the outer metallic tubular 60. As previously discussed, the innermetallic tubular 54 and the electrically conductive material 56 mayprovide a separate conductive path than the outer metallic tubular 60.The resistance of the outer metallic tubular 60 (e.g., 24 Ω/km or 7.3Ω/k′) may often be higher than the resistance of the inner metallictubular 54 and the electrically conductive material 56. However, thehigher resistance may be improved (i.e., lowered) if a DC or lowfrequency AC current returns through the outer metallic tubular 60 andalso returns through the coiled tubing 24 of FIG. 1 . The coiled tubing24 has a relatively smaller resistance (0.5 Ω/k′). In the examples ofFIGS. 2A and 2B, the cable 33 may be mechanically and electricallycoupled to the coiled tubing 24 to allow electrical current to passthrough the coiled tubing 24. The electrical coupling to the coiledtubing 24 may include, in some examples, mechanical fasteners thatmechanically couple the cable 33 and the coiled tubing 24 with the outermetallic tubular 60 and the coiled tubing 24 in electrical contact. Inother examples, an electrically conductive medium, such as brazing,soldering, or welding, may be used to mechanically and/or electricallyjoin the outer metallic tubular 60 and the coiled tubing 24. In certainembodiments, the electrical coupling to the coiled tubing 24 may includesimply deploying the cable 33 in close proximity (e.g., in directcontact) to the coiled tubing 24.

The cable 33 may also be employed to transmit electrical power andtelemetry signals via the inner metallic tubular 54, the electricallyconductive material 56, and the outer metallic tubular 60. For telemetrypurposes, the cable 33 may be operated in different transmission modes.For example, a telemetry signal may propagate down through the innermetallic tubular 54 and the electrically conductive material 56 andpropagate up through the coiled tubing 24. The telemetry signal includesa frequency and an amplitude that convey information to the electricaldevice 29 and back to the control unit 44. At a low frequency (e.g.,below about 1 kHz), the telemetry signal follows a flow path downthrough the inner metallic tubular 54 and the electrically conductivematerial 56, and returns through a return flow path that includes thecoiled tubing 24. As the frequency of the telemetry signal increases toa high frequency (e.g., above about 1 kHz), however, electromagneticforces cause the current to propagate through the outer metallic tubular60 rather than the coiled tubing 24. The outer metallic tubular 60exhibits lower magnetic energy than the coiled tubing 24 when thetelemetry signals are propagated at higher frequencies.

As stated above, the outer metallic tubular 60 has higher resistancecompared to the coiled tubing 24. So a diversion of current from thecoiled tubing 24 to the outer metallic tubular 60 may result in signallosses that limit the available signal bandwidth for telemetryapplications. Signal losses may be especially encountered for longdistance applications, which may occur in production formations 15 at adepth of 5,000 meters (˜16,000 feet) or more. Although theelectromagnetic waveguides 50 may be operable to convey signalsdownhole, certain embodiments of cable 33 may use the electromagneticwaveguides to convey optical signals uphole (e.g., from the electricaldevice 29), while using the inner metallic tubular 54, electricallyconductive material 56, and the outer metallic tubular 60 to conveysignals downhole (e.g., to the electrical device 29).

To further reduce the resistance and improve the power andcommunications efficiency of signals returning from the electricaldevice 29, an additional electrically conductive material may be appliedto the interior surface of the outer metallic tubular 60. For example,FIG. 4 shows a cross-section view of the cable 33 including anadditional electrically conductive material 62 applied between theelectrically insulating layer 58 and the outer metallic tubular 60, inaccordance with one or more embodiments. As non-limiting examples, theadditional electrically conductive material 62 may comprise anelectrically conductive cladding of copper, aluminum, silver, or anyother suitable conductor applied to the interior surface of the outermetallic tubular 60. The additional electrically conductive material 62may include conductive tape (e.g., copper tape) applied between theelectrically insulating layer 58 and the outer metallic tubular 60. Theadditional electrically conductive material 62 may also includeconductive wires (e.g., copper wires) served or braided over theelectrically insulating layer 58 before enclosing the assembly in theouter metallic tubular 60. Employing copper wire or copper tape insidethe outer metallic tubular 60 may require increasing the outer diameterof the cable 33, reducing the thickness of the electrically insulatinglayer 58, or reducing the outer diameter of inner metallic tubular 54.However, a thinner electrically insulating layer 58 may result inreducing power handling capacity and increase the capacitance, reducinga benefit of the lower resistance path at telemetry signals with highfrequencies.

In manufacturing the cable 33, one or more layers may each be formed asa structurally separate tubing or concentric layer before combining withanother layer. Alternatively, a first layer may be formed and then asecond layer may be formed on the first layer. For example, theelectrically conductive material 56 may be formed by electroplating orotherwise depositing on the inner metallic tubular 54.

It should be understood that the outer metallic tubular 60 may be anoptional protective layer to resist corrosion and abrasion from thefluid encountered in the coiled tubing. The power and communicationscable 33 may be employed as an integrated assembly, without theprotective layer, including the electromagnetic waveguides 50, the innermetallic tubular 54, the electrically conductive material 56, theelectrically insulating layer 58, and the additional electricallyconductive material 62.

It should be appreciated that the power and communications cabledescribed herein provides a cable capable of withstanding the harshenvironment encountered inside coiled tubing, while offering suitableelectrically conductive paths for transmission of power andcommunications signals. The alloy employed for the outer metallictubular provides a protective layer for the waveguides to withstand thehigh pressures and corrosive, abrasive fluids encountered in coiledtubing. With a conductive layer applied inside the outer tubular, thecable 33 provides a suitable conductor for transmission of power andcommunication signals for downhole electrical equipment such as depictedin FIGS. 3 and 4 .

One or more specific embodiments of the power and communications cableand coiled tubing system have been described. In an effort to provide aconcise description of these embodiments, all features of an actualimplementation may not be described in the specification. It should beappreciated that in the development of any such actual implementation,as in any engineering or design project, numerousimplementation-specific decisions must be made to achieve thedevelopers' specific goals, such as compliance with system-related andbusiness-related constraints, which may vary from one implementation toanother. Moreover, it should be appreciated that such a developmenteffort might be complex and time-consuming, but would nevertheless be aroutine undertaking of design, fabrication, and manufacture for those ofordinary skill having the benefit of this disclosure.

Certain terms are used throughout the description and claims to refer toparticular features or components. As one skilled in the art willappreciate, different persons may refer to the same feature or componentby different names. This document does not intend to distinguish betweencomponents or features that differ in name but not function.

Reference throughout this specification to “one embodiment,” “anembodiment,” “an embodiment,” “embodiments,” “some embodiments,”“certain embodiments,” or similar language means that a particularfeature, structure, or characteristic described in connection with theembodiment may be included in at least one embodiment of the presentdisclosure. Thus, these phrases or similar language throughout thisspecification may, but do not necessarily, all refer to the sameembodiment.

The embodiments disclosed should not be interpreted, or otherwise used,as limiting the scope of the disclosure, including the claims. It is tobe fully recognized that the different teachings of the embodimentsdiscussed may be employed separately or in any suitable combination toproduce desired results. In addition, one skilled in the art willunderstand that the description has broad application, and thediscussion of any embodiment is meant only to be exemplary of thatembodiment, and not intended to suggest that the scope of thedisclosure, including the claims, is limited to that embodiment.

In addition to the embodiments described above, embodiments of thepresent disclosure further relate to one or more examples described inthe following paragraphs:

An example may include a coiled tubing locatable in a wellbore, a powerand communications cable positioned along the coiled tubing. The powerand communications cable may include an electromagnetic waveguide, aninner metallic tubular surrounding the electromagnetic waveguide, anelectrically conductive material surrounding the inner metallic tubular,an electrically insulating material surrounding the electricallyconductive material, and an outer metallic tubular resistant tocorrosion and abrasion surrounding the electrically insulating layer.The example system may include an electrical device locatable in thewellbore and coupleable to the cable and a control unit coupleable tothe cable and operable to supply power to and communicate with theelectrical device via the power and communications cable.

The example of the power and communications cable may include anadditional electrically conductive material positioned between theelectrically insulating layer and the outer metallic tubular. Theadditional electrically conductive material may include a resistancethat is lower than a resistance of the outer metallic tubular.

Examples of the power and communications cable may include an additionalelectromagnetic waveguide inside the inner metallic tubular. Examples ofthe electromagnetic waveguide or the additional electromagneticwaveguide may also include a fiber optic cable. Examples of the outermetallic tubular may include an alloy having nickel, iron, chromium,molybdenum, copper, manganese, and titanium. Examples of the outermetallic tubular may have an outer diameter of between 3 millimeters and6 millimeters. Examples of the control unit may communicate with theelectrical device with a high frequency signal.

Examples of the disclosed embodiments may include a power andcommunications cable, comprising: an electromagnetic waveguide, an innermetallic tubular surrounding the electromagnetic waveguide, anelectrically conductive material surrounding the inner metallic tubular,an electrically insulating material surrounding the electricallyconductive material, and an outer metallic tubular resistant tocorrosion and abrasion and surrounding the electrically insulatinglayer.

Examples of the power and communications cable may include an additionalelectrically conductive material positioned between the electricallyinsulating layer and the outer metallic tubular. The additionalelectrically conductive material may include a resistance that is lowerthan a resistance of the outer metallic tubular. Examples of the powerand communications cable may include an additional electromagneticwaveguide inside the inner metallic tubular. The electromagneticwaveguides of these embodiments may include fiber optic cables. Examplesof the electrically conductive material may include copper tape. Theouter metallic tubular may be made from an alloy comprising nickel,iron, chromium, molybdenum, copper, manganese, and titanium. The outermetallic tubular may have an outer diameter of 3 to 6 millimeters.

Examples of a method of conveying power and communication signals in awellbore may include sending a first signal along a power andcommunications cable to an electrical device located downhole in thewellbore, the first signal propagating downhole through an innermetallic tubular surrounding a waveguide within the power andcommunications cable. The method may include receiving a second signalfrom the electrical device along the power and communications cable, thesecond signal propagating uphole through an outer metallic tubularwithin the power and communications cable. The outer metallic tubularmay surround and protect the inner metallic tubular and the waveguide.The second signal may propagate uphole through an additionalelectrically conductive material positioned around the inner metallictubular. The method may include receiving a third signal from theelectrical device, the third signal propagating through the waveguide.The method may also include receiving a fourth signal from theelectrical equipment, the fourth signal propagating through anadditional waveguide located within the inner metallic tubular. Incertain embodiments, the first signal, the second signal, or bothcomprise a high frequency signal.

What is claimed is:
 1. A method of conveying power and communicationsignals in a wellbore comprising: sending a first communication signalalong a power and communications cable to an electrical device locateddownhole in the wellbore, wherein the first communication signalpropagates downhole through an inner metallic tubular surrounding awaveguide within the power and communications cable; receiving a secondcommunication signal from the electrical device along the power andcommunications cable, wherein the second communication signal propagatesuphole through an outer metallic tubular within the power andcommunications cable, and wherein the outer metallic tubular surroundsand protects the inner metallic tubular and the waveguide; and whereinthe second communication signal also propagates uphole through anelectrically conductive material positioned around the inner metallictubular and inside the outer metallic tubular.
 2. The method of claim 1,comprising receiving a third communication signal from the electricaldevice, wherein the third communication signal propagates through thewaveguide.
 3. The method of claim 2, comprising receiving a fourthcommunication signal from the electrical equipment, wherein the fourthcommunication signal propagates through an additional waveguide locatedwithin the inner metallic tubular.
 4. The method of claim 1, wherein thefirst communication signal, the second communication signal, or bothcomprise a high frequency signal.